Conventionally, a power window system of a vehicle has a motor having a speed-reduction mechanism therein for its drive source. A motor is known in which a circuit board is disposed in a gear housing enclosing the speed-reduction mechanism (refer to JP-2002-262516-A for example).
The gear housing of the motor has an opening portion that faces a motor portion of the motor and a board-installing portion that installs the circuit board inserted through the opening portion in an axial direction of the motor portion. In contrast, a brush holder is fitted to an opening portion of a yoke housing that defines the motor portion. The brush holder is integrally formed with a cover member that blocks the opening portion of the gear housing. Bolts fasten the yoke housing to the gear housing. The motor has a configuration that a fastening torque of the bolts blocks the opening portion of the gear housing with the cover member and clamps the circuit board between the cover member and a board-installing portion's face opposite to the opening portion (a bottom face of the board-installing portion) to hold the circuit board in the board-installing portion.
According to the above-described configuration, however, when a dimensional error is introduced in a direction of pushing the circuit board and the cover member tightly onto each other for instance, the circuit board pushes the cover member to be lifted off the opening portion of the gear housing. This causes a problem of generating a gap between the opening portion and cover member to spoil a seal quality therebetween. On the contrary, when the dimensional error is introduced in a direction of detaching the circuit board and the cover member from each other, the cover member and the bottom face of the board-installing portion cannot clamp the circuit board therebetween. This causes a problem that the circuit board rattles in the board-installing portion and generates an unusual noise. Thus, it is necessary to increase a dimensional accuracy of these components. A control of the dimensional accuracy, however, requires a cumbersome work.
The present invention is achieved to solve the above-described issues. The object of the present invention is to provide a motor configured to have a gear housing that installs a circuit board therein inserted through an opening portion thereof and that a cover member that blocks the opening portion, which can secure a seal quality of the cover member and prevent a rattle of the circuit board even when a dimensional error is introduced both in a direction of pushing the circuit board and the cover member onto each other and in a direction of detaching them from each other.